cr250 engine in a 250r frame?

[mineralgrey01gt]

will this still be powerful like the 250r engines? Is it a waste of time? I can get one pretty cheap locally and am wondering if its better to just get a 250r engine instead of this.

[86 Quad R]

Originally posted by my88r
well you can put one in there takes some work i dont know if the stock motor mounts will work check servicehonda.com they make a bike with that motor so you can go off of that


i too aint sure if the cr engines have similar mounts or not but the sevice hona quad "my88r" speaks of is a 400ex conversion with a cr engine in it, not a R frame with a cr engine.

FYI the cr engine does NOT have a counter balancer in it and unless installed properly(special built cusioning mounts). will give you fits with vibration.

[my88r]

no here that did that i think one of them he did to a r frame. you can look and see how they done it on servicehonda.com thats all i know its a 400ex

[RICKY BOBBY]

I think that cr250 is as tall as the crf450, and the mounts are very similair .

[Toadz400]

It'll work and it'll be a lot better than a 250R engine in the end. The CR250 puts out a lot more power than the ATV engine and it's more comforting knowing you have a much newer engine. As for the mounts, I believe they're pretty similar but you will need to use a lot of rubber and other insulators to keep that vibration down!

[CorvetteZ06]

its not worth the vibration you will go through. get a decent 250R motor, go through the bottom end, and put on a powervalve cylinder. you will have something nice and reliable and with good power.

[chris46250r]

Originally posted by CorvetteZ06
its not worth the vibration you will go through. get a decent 250R motor, go through the bottom end, and put on a powervalve cylinder. you will have something nice and reliable and with good power.


AMEN !!!

[406Z26]

IIRC the CR is a 5 speed and the TRX is a 6 speed.

[my88r]

doesnt matter that cr is alot faster

[86 Quad R]

Originally posted by my88r
doesnt matter that cr is alot faster

with the cr250's power to weight ratio. it may seem that way to you. add that same engine to a much heavier quad and the acceleration will slow.

not saying that the cr engine is slow by no means but a (stock)trx engine can be VERY easily modded to match or EXCEED the cr engines torque.

[Rich250RRacer]

Originally posted by 86 Quad R
with the cr250's power to weight ratio. it may seem that way to you. add that same engine to a much heavier quad and the acceleration will slow.

not saying that the cr engine is slow by no means but a (stock)trx engine can be VERY easily modded to match or EXCEED the cr engines torque.

Keep in mind that a stock 250R motor is about 30 horsepower, a stock 92-01 CR motor (which would be my choice, but the 86-91 will mount easier and the HP numbers are close) is between 49 and 52 ACTUAL horsepower. If you can find a way to isolate the vibration, the CR motor is leaps and bounds better, no question about it. And before anyone on here says the CR transmission won't hold up, keep in mind that these CR motors are the number one choice for micro-sprint cars, and most of them are running with stock trans gears, plus they're not using a clutch, which puts a serious beating on it. And they weigh 500 lbs or more. They seem to hold up pretty well.

[trx250r180]

dont do it!!,i had the jp racing one that was built in 92 for the mickey thompson series,it was fast but made my arms knumb,was a real tire fryer and didnt have the tourque of a fourtrax engine,throw a bigbore niks cyl on a 250r engine and you will have plenty of power and not wear yourself out riding it

[mineralgrey01gt]

thanks for all the replies everyone! So I take it that it vibrates almost as bad as a CR500 engine on a 250r? If so I dont think I want to fight with that. Is there anyway to get the vibration down?

[Toadz400]

Originally posted by mineralgrey01gt
thanks for all the replies everyone! So I take it that it vibrates almost as bad as a CR500 engine on a 250r? If so I dont think I want to fight with that. Is there anyway to get the vibration down?

Incorporate rubber into all your mounts, especially the handlebars, foot pegs and engine mounts. I remember reading an article that was a few years old before the 450 quads came out where a racing group was running a CR250 engine in a 250R frame. They used rubber mounts wherever they could and they said the vibration was close to the same as the 250R engine while still putting out way more power.

[mineralgrey01gt]

thanks man, i figured rubber motor mounts would help, i can get all the rubber mounts i would need for the complete bike :D i may go that route with the engine. Do they make some nice big bore kits for the cr250 engines? Will a trx 250r exhaust work on it? Or will I need the cr250 exhaust?

[my88r]

cr exhast wont fit the trx will but it has to have a trx flange

[2muchquad]

Its amazing at how the opinions form from lack of understanding.The cr250 motor has considerably more hp than a stock 250r.Vibration is only more noticeable when reving the bike up in neutral,its not an issue under riding conditions.I have had a cr250 motor in a blaster for almost 3yrs,no problems.Tranny still holding up fine.this motor is going into a 250r frame as we speak.Weld the flange from a cr250 pipe onto a 250r pipe after its trimmed and it can be used.I did have insulated steering stem but thats it for vibration control,no rubber mounts etc.use bolts that fit the holes in the motor mounts instead of bolts too small and you'll be fine.This is like beating a dead horse here..;)

[2muchquad]

an old pic..

[beobe99]

I would listen to the above. most info you get on here is from someone that heard about someone that had the experience.

As for Vibration I think theres tons of things you can do.. most proven and some ive come up with hehe!

-Silicon from home depo (calk gun style tube) in the handle bars and maybe down the steering stem (not TO much for adding weight issues)

-anti-vibe stem of course

-flex bars

-rubber washers behind all bolts holding the mounts (prob does nothing but what the hell) I wouldnt make a rubber mounting set up like a car in fear if the engine wobbling or chain poping.

-I cut up a old thicker gel hand grip wraping it around the upper steering stem part of the frame (the part of the frame thats round) using a Clamp (to givethe effect that i was grabing onto the frame real hard to damping the vibration) It's under the plastics so it doesn't look like crap hehe!

I've been TRYING to find some sort of bushing thats square in the middle being the size of the square frame rails and round on the outside for a clamp but no luck. You mentioned you could get bushings? anything like that? Id be interested..

I think you should do the CR engine and make it clean as hell looking and running.. If i could weld id be all about doing nothing but Hybrids..

[Toadz400]

Originally posted by beobe99
I would listen to the above. most info you get on here is from someone that heard about someone that had the experience.

As for Vibration I think theres tons of things you can do.. most proven and some ive come up with hehe!

-Silicon from home depo (calk gun style tube) in the handle bars and maybe down the steering stem (not TO much for adding weight issues)

-anti-vibe stem of course

-flex bars

-rubber washers behind all bolts holding the mounts (prob does nothing but what the hell) I wouldnt make a rubber mounting set up like a car in fear if the engine wobbling or chain poping.

-I cut up a old thicker gel hand grip wraping it around the upper steering stem part of the frame (the part of the frame thats round) using a Clamp (to givethe effect that i was grabing onto the frame real hard to damping the vibration) It's under the plastics so it doesn't look like crap hehe!

I've been TRYING to find some sort of bushing thats square in the middle being the size of the square frame rails and round on the outside for a clamp but no luck. You mentioned you could get bushings? anything like that? Id be interested..

I think you should do the CR engine and make it clean as hell looking and running.. If i could weld id be all about doing nothing but Hybrids..

Some very good ideas there. Welding isn't that hard as long as you are able to understand how it works and what you're doing to the metal. I would pick up some books on the different types of welding on different materials and then pick yourself up a MIG welder. It's very easy to do once you have a lot of practice and like I said understand what it is you're doing. It's very rewarding to be able to do your own work like that.

[beobe99]

Originally posted by Toadz400
Some very good ideas there. Welding isn't that hard as long as you are able to understand how it works and what you're doing to the metal. I would pick up some books on the different types of welding on different materials and then pick yourself up a MIG welder. It's very easy to do once you have a lot of practice and like I said understand what it is you're doing. It's very rewarding to be able to do your own work like that.

Thanks man.. I've been debating getting a Mig and messing around with it.. trial and error you know.. Being able to weld and having the welder would def. change what goes on in my garage in a very good way.. thanks

[2muchquad]

Thats what i did about 7 yrs ago.I bought my own mig and pretty much learned on the job.;)

[Toadz400]

Originally posted by beobe99
Thanks man.. I've been debating getting a Mig and messing around with it.. trial and error you know.. Being able to weld and having the welder would def. change what goes on in my garage in a very good way.. thanks

Yea, just find a decent MIG and grab some scrap metal and have at it. Best way to learn along with reading up on it. You won't regret it and it definitely pays off in the end, especially when you're able to make your own parts/tools that would've cost you major.